Sweep methods for parallel computational geometry

In this paper we give efficient parallel algorithms for a number of problems from computational geometry by using versions of parallel plane sweeping. We illustrate our approach with a number of applications, which include:

General hidden-surface elimination (even if the overlap relation contains cycles).

CSG boundary evaluation.

Computing the contour of a collection of rectangles.

Hidden-surface elimination for rectangles.

There are interesting subproblems that we solve as a part of each parallelization. For example, we give an optimal parallel method for building a data structure for line-stabbing queries (which, incidentally, improves the sequential complexity of this problem). Our algorithms are for the CREW PRAM, unless otherwise noted.     

An operational semantics for Paragon: A design notation for parallel architectures

The need to design and verify architectures to support parallel implementations of declarative languages has led to the development of a novel language, called Paragon, which bridges the gap between the top-level specification of the abstract machine, and its detailed implementation in terms of parallel processes and message passing. The central technical contributions in this paper are:

? The introduction and specification of Paragon, a parallel object-oriented language based on graph rewriting and message passing principles.

? An illustration of the approach at work in the design of a parallel supercombinator graph reduction machine.

? A sketch proof that this design meets the requirements statement.

     

Separability and one-way functions

We settle all relativized questions of the relationships between the following five propositions:

• P = NP.
• P = UP.
• P = NP $\cap$ coNP.
• All disjoint pairs of NP sets are P-separable.
• All disjoint pairs of coNP sets are P-separable.

We make the first widespread use of variations of generic oracles to achieve the necessary relativized worlds.     

Kernel language KLND

This paper presents a kernel language KLND on the basis of analysing the kernel languagerequirements of new generation computer systems. These requirements are: the ability ofknow-ledge processing, the parallelism, the elegant mathematical properties of the comput-ation model which is appropriate for working as the basis of the novel architecture design, andthe suitability for writing large scale softwares. The main features of KLND are as follows: 1. several new language concepts. 2. the modularity, 3. the unification of logical and functional programming styles, 4. the exploitation of the parallelism. 5. the introduction of the type concept, 6. the introduction of the storage concept.     

The Parallel Complexity of Graph Canonization Under Abelian Group Action

We study the problem of computing canonical forms for graphs and hypergraphs under Abelian group action and show tight complexity bounds. Our approach is algebraic. We transform the problem of computing canonical forms for graphs to the problem of computing canonical forms for associated algebraic structures, and we develop parallel algorithms for these associated problems.

1. In our first result we show that the problem of computing canonical labelings for hypergraphs of color class size 2 is logspace Turing equivalent to solving a system of linear equations over the field $\mathbb {F} _{2}$ . This implies a deterministic NC ² algorithm for the problem.
2. Similarly, we show that the problem of canonical labeling graphs and hypergraphs under arbitrary Abelian permutation group action is fairly well characterized by the problem of computing the integer determinant. In particular, this yields deterministic NC ³ and randomized NC ² algorithms for the problem.

     

Einsatzpotenziale von XML in Business-Intelligence-Systemen

This article describes the actual applications of XML in the context of Business- Intelligence-Systems (BI). The potentials and synergies of XML and BI will be emphasized.

1. XML applications can be found within all levels of BI-systems.
2. The application of core-standards will be introduced as well as the possibilities of BI specific-standards.
3. The discussion of the impact of XML for BI-systems follows along the dimensions: externalisation, integration, standardisation and rationalization.

     

Thinking in parallel: four steps to Parlog

If you are familiar with Prolog but not with Parlog then this tutorial is aimed at you. In what follows I attempt to:

? explain the basics of Parlog

? demonstrate that Parlog programs can be powerful and elegant

? discuss the relationship of Parlog to Prolog, and

? identify some resources which will take you further.

These are what I call ‘four steps to Parlog’.     

Specification and refinement of networks of asynchronously communicating agents using the assumption/commitment paradigm

This paper presents an assumption/commitment specification technique and a refinement calculus for networks of agents communicating asynchronously via unbounded FIFO channels in the tradition of Kahn.

We define two types of assumption/commitment specifications, namely simple and general specifications.

It is shown that semantically, any deterministic agent can be uniquely characterized by a simple specification, and any nondeterministic agent can be uniquely characterized by a general specification.

We define two sets of refinement rules, one for simple specifications and one for general specifications. The rules are Hoare-logic inspired. In particular the feedback rules employ invariants in the style of a traditional while-rule.

Both sets of rules have been proved to be sound and also (semantic) relative complete.

Conversion rules allow the two logics to be combined. This means that general specifications and the rules for general specifications have to be introduced only at the point in a system development where they are really needed.

     

An approach to the DIN Kernel Lisp definition

A DIN Kernel LISP Draft (DKLisp) has been developed by DIN as Reaction to Action D1 (N79), short term goal, of ISO WG16. It defines a subset language, as compatible as possible with the ANSICommon-Lisp draft, but also with theEuLisp draft. It combines the most important LISP main stream features in a single, compact, but nevertheless complete language definition, which thereby could be well suited as basis for a short term InternationalLisp Standard. Besides the functional and knowledge processing features, the expressive power of the language is well comparable with contemporary procedural languages, as e.g. C++ (of course without libraries). Important features ofDKLisp are:

to be a “Lisp-1,” but allowing an easy “Lisp-2” transformation;

to be a simple, powerful and standardized educationalLisp;

to omit all features, which are unclean or in heavy discussion;

DKLisp programs run nearly unchanged inCommon-Lisp;

DKLisp contains a simple object and package system;

DKLisp contains those data classes and control structures also common to most modernLisp and non-Lisp languages;

DKLisp offers a simple stream I/O;

DKLisp contains a clean unified hierarchical class/type system;

DKLisp contains the typical “Lisp-features” in an orthogonal way;

DKLisp allows and encourages really small but powerful implementations;

DKLisp comes in levels, so allowing ANSICommon-Lisp to be an extension ofDKLisp level-1.

The present is the second version of the proposal, namely version 1.2, with slight differences with respect to the one sent to ISO. Sources of such changes were the remarks generously sent by many readers of the previous attempt.     

Konsultative Assistenzsysteme für e-Government

Consultative Assistance Systems (CASS) enhance today’s transaction-oriented applications by case-driven, rule-based and interactive components geared towards individual needs of the end-user.

1. CASS supports in the resolution process with rare cases, which are typically complex in nature.
2. CASS guides the end-user in finding a solution that covers all legal and economical aspects of each case.
3. The example described in this article represents a CASS which supports the complex process of public procurement under the tendering by-laws. The application architecture used in this example can be transferred to many eGovernment scenarios.

     

Integrated systems I: Design principles

The following design principles are being used in an ongoing project to realize an integrated family of rule based systems that can be easily used separately or together in different combinations to solve problems common to many different disciplines. Some essential features of this family are:

1. Individual members can be used in the normal way as user-friendly rule based systems or they can be transparently invoked by other user-friendly rule based systems without interrogating users.
2. The knowledge (or rule) bases of key members do not mimic the perceived mode of human thought; therefore, they can predict events that cannot be predicted by the state-of-the-art alone.
3. The Law of Conservation of Mass/Energy is used to detect and correct computational errors.

     

Inventive machine: Second generation

Inventive Machine project is the matter of discussion. The project aims to develop a family of AI systems for intelligent support of all stages of engineering design. Peculiarities of the IM project:

1. deep and comprehensive knowledge base — the theory of inventive problem solving (TIPS)
2. solving complex problems at the level of inventions
3. application in any area of engineering
4. structural prediction of engineering system development

The systems of the second generation are described in detail     

RaumComputer

The RoomComputer is an embedded system and as such offers unprecedented chances to manage buildings. Several RoomComputers can be networked via the Intra-/Internet, which makes it possible to monitor, control, and manage rooms and buildings on a unified worldwide accessible platform, irrespective of any particular local technology. It can be easily installed in any building and gives access to a full set of services. It implements a distributed system, which provides secure and controlled access to services like

1. control of light, heating, ventilation, air and climate
2. communication facilities like unified messaging, telephone, fax, etc.
3. reservation of rooms and required resources
4. localization of persons and equipment within rooms and buildings
5. entrance control (i.e. locking/unlocking doors)
6. organization of maintenance and house keeping, and
7. charging and billing.

     

Optimal parallel algorithms for rectilinear link-distance problems

We provide optimal parallel solutions to several link-distance problems set in trapezoided rectilinear polygons. All our main parallel algorithms are deterministic and designed to run on the exclusive read exclusive write parallel random access machine (EREW PRAM). LetP be a trapezoided rectilinear simple polygon withn vertices. InO(logn) time usingO(n/logn) processors we can optimally compute:

1. Minimum réctilinear link paths, or shortest paths in theL ₁ metric from any point inP to all vertices ofP.
2. Minimum rectilinear link paths from any segment insideP to all vertices ofP.
3. The rectilinear window (histogram) partition ofP.
4. Both covering radii and vertex intervals for any diagonal ofP.
5. A data structure to support rectilinear link-distance queries between any two points inP (queries can be answered optimally inO(logn) time by uniprocessor).

Our solution to 5 is based on a new linear-time sequential algorithm for this problem which is also provided here. This improves on the previously best-known sequential algorithm for this problem which usedO(n logn) time and space.5 We develop techniques for solving link-distance problems in parallel which are expected to find applications in the design of other parallel computational geometry algorithms. We employ these parallel techniques, for example, to compute (on a CREW PRAM) optimally the link diameter, the link center, and the central diagonal of a rectilinear polygon.     

High-speed tools for Global Information Management I. Information processing and retrieval

The general specifications and design for a High-Speed General Information Management System, HSGIMS, to serve as the basis for a Global Information Network are given. Some of the key specifications that have been confirmed in experiments with a prototype of the HSGIMS are:

1. Information (or data) and Question-type (or logical data) independence.
2. Very small bounded search times that are independent of the amount of information that is managed and can be computed exactly.
3. A fool-proof security system that can be used to protect databases against viruses and can also be easily invoked to deny unauthorized access by users.
4. Efficient use of all storage and communications resources.

     

Enhanced qualitative physical reasoning system: Qupras

There are many expert systems that use experimental knowledge for diagnostic analysis and design. However, there are two problems for systems using only experiential knowledge:

1. unexpected problems cannot be solved and
2. acquiring experiential knowledge from human experts is difficult.

To solve these problems, general principles or basic knowledge must be added to expert systems in addition to the experimental knowledge. In response, we previously proposed Qupras (Qualitative physical reasoning system) as a framework for basic knowledge. This system has two knowledge representations, one related to physical laws and the other to objects. By using this knowledge, Qupras reasons about the relations among physical objects, and predicts the next state of a physical phenomenon. Recently, we have improved some of Qupras’ features, and this pater desctibes the following main enhancements:

1. inheritance for representation of objects,
2. new primitive representations to describe discontinuous change, and
3. control features for effective reasoning.

     

Electrokinetic microslit experiments to analyse the charge formation at solid/liquid interfaces

Electrokinetic effects play an important role in microfluidics and nanofluidics. Although the related phenomena are often utilized to control fluid flow and sample transport in lab-on-a-chip devices, their dependency on the surface charges on the channel walls often remain enigmatic. This is mainly due to the lack of adequate experimental methods to analyse the electrical charging of solid/liquid interfaces of interest. To address this need, an experimental set-up—designated as microslit electrokinetic set-up (MES)—has been recently developed and applied for the investigation of charge formation processes at planar solid/liquid interfaces. The device permits to perform streaming potential and streaming current measurements across a rectangular streaming channel formed by two parallel sample carriers (20×10×3 mm³) at variable distance allowing for the determination of the surface conductivity. Utilizing the MES, charge characteristics can be determined for a wide variety of materials prepared as thin films on top of planar glass substrates. Streaming potential and streaming current data permit to investigate the mechanisms of charge formation while surface conductivity data provide information about mobile charge carriers located in different zones at the interface. The applicability of this advanced experimental approach is demonstrated with examples obtained for surfaces with different levels of complexity:

1. Preferential ion adsorption onto unpolar fluoropolymer (Teflon^® AF) films was characterized in simple electrolyte solutions; the results were quantitatively evaluated with respect to interfacial ion concentrations.
2. Interrelation of charge density and conformation of grafted poly(L-glutamic acid layers) were unravelled from the determination of pH-depended variations of surface conductivity and layer thickness.
3. The impact of spatial confinements of surface functional groups on their acid–base behaviour was studied with self-assembled monomolecular films of alkanethiols chemisorbed on gold.
4. Charging of and ion mobility within poly(acrylic acid) (PAA) brushes prepared by a Langmuir–Blodgett technique were analysed at varied pH and ionic strength.
5. Interfacial modes of adsorbed proteins were distinguished at two polymer surfaces with varied hydrophobicity/charge density.